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Knee Pain When Bending

16th May 2021

Knee pain is such a common ailment, throughout all different ages of our population. Do you suffer from knee pain? Is it a constant or is it only when you do certain things?

A common cause of knee pain is when bending the knee. Does this sound like your pain?

You won’t be the only person who has knee pain like this. When you bend your knee it requires you to put all of your weight through the knee and force goes through the very front of the knee.

If your knee joint is already painful then this can be an obvious cause and the pain can become worse

When standing you may not get any pain, as your bodyweight is shared between both of your lower limbs and also the ankle and hip joints.

When you then place the demand of the full body weight through a flexed knee joint then it can cause a painful response.

There are multiple causes for having knee pain when bending the knee – it could be any of the structures around the knee or it may even be a long standing condition.

For many people, bending down and bending the knee is an essential part of everyday life and this can often present a big problem for your day to day mobility.

Simple everyday tasks and household activities can become difficult to maintain when faced with lots of repetitive bending of the knee. Often, people will start to adapt their movement to avoid bending the knee.

This is not advised as it will cause pain in other areas but will also mean losing function in the knee and/or making it more painful.

Our guide to knee pain when bending will help you to understand your knee and why you get pain. This article may be helpful for a friend or family member suffering from this problem.

The key to reducing knee pain is being mobile and keeping your lower limbs strong, you may find you have to temporarily cope with pain whilst trying to get this issue better, however that is perfectly normal.

The good news is that you can fix this problem – follow our advice and we can guide you to recovery.




To understand why we get pain in the knee when it bends, we must understand the anatomy of the knee and the structures that come under pressure when the knee is bent.

The knee joint is made up of 3 main bones which include the thigh bone, shin bone and knee cap.

The main load bearing joint of the knee is the tibiofemoral joint – comprising of the shin and thigh bone as well as the kneecap.

The knee cap (patella) and the femur fit together to make the patellofemoral joint – the kneecap slides over the femur in a small groove when the knee bends and extends to allow smooth movement – a lot of pressure goes through the front of the knee in this joint when it is bent.

Cartilage within the middle of the knee joint is called the meniscus, this acts as the shock absorber for the knee and also facilitates smooth movement in flexion and extension when we bend the knee.

Underneath the patella there are fat pads and bursa which allow for cushioning and proper function of the kneecap as it moves. If there is any discomfort in these tissues then it will add to pain in the knee when bending.

Tendons are the structures which attach muscle to bone. The quad tendon linking the quads to the kneecap and the patella tendon linking the kneecap to the shin. Tendons are needed to attach muscle to bones but also to generate movement and force. The patella tendon is commonly linked to pain in the front of the knee, especially when bending. If there is any tendinitis – this will be a main cause of pain in the knee when bending.

Muscles move the knee and help it be controlled when it bends. They are vital to how we experience pain in the knee joint because if the knee is weak then more load is placed through the bones and cartilage – this can cause pain.

Having strong hamstrings which secure the knee and stop pressure at the front – are key. When we bend the knee – the hamstrings pull on the shin securely fix the knee. If we have weakness in the hamstrings then this will cause pain at the front of the knee during bending.

Strong quadriceps are also critical for helping control the knee when going in to bending positions. Weakness in the quads adds pressure to the joint which over time can lead to pain developing.

Having a strong knee helps to share load more effectively and helps us to remain pain free. Weakness within the knee promotes more pressure through the joint of the knee, which can be a primary driver of pain when we bend the knee.




Here are some of the common causes of why we get pain in the knee when bending.


OsteoarthritisThis will be more common in the population, over 50. Reduction of a smooth surface within the knee joint cartilage over time can lead to irritation. This will be more noticeable when bending the knee as more pressure goes through the joint. Arthritis within the patellofemoral joint, involving the kneecap will cause pain when bending as when we bend the kneecap slides over the femur – this can be particularly irritating

Leg Length Differencehaving different length legs is a common issue – most people do not experience any pain but some it can cause a lot of problems if the difference is significant. If this is the case – it may be difficult to distribute your weight properly when the knee bends and more pressure may be placed on the knee than another.

Knee cap pain Common causes of kneecap pain which can be made worse when bending the knee are fat pad impingement, patella malalignment and patella osteoarthritis – as previously mentioned. When bending the knee – force goes in to the structures at the front and if there is already pain in these structures, this can exacerbate it.

TendonitisThis can be placed with anterior knee pain, having patella and quadriceps tendinitis is inflammation of the tendons which can cause pain and weakness of the tendons which help to bend the knee.

Muscle weaknessAs previously discussed, weakness increases pressure on the knee, having strength takes pressure off the knee. You can’t go wrong getting your knees strong.




Here is a common list of symptoms you may get when having a painful bend in the knee. This list is not exclusive and everyone will be different.


Paintypically experienced around the front of the knee. The main symptom of pain is typically from aggravated frontal structures of the knee that are not tolerating bending very well.  The nature of pain experienced may differ from a dull pain to more of a sharp pain depending on how bad your knee pain is and also how quickly you bend the knee.

Swellingif repetitive bending of the knee when painful has been performed and tissues are aggravated – the knee may swell up as a protective response. Bending the knee can exert pressure on sore tissues causing them to become inflamed and sore – this starts the swelling response. If you have existing swelling, this contributes further to weakening of the knee as you may not be able to use it fully when it is swollen.

Knee Instabilityif the pain in the knee becomes too severe it can occasionally lead to the knee giving way. Pain can inhibit muscles and stop them from working – so when bending if it is too painful the knee may simply fall from underneath you. Important to note, if the knee gives way without pain – this is a sign of structural damage and it should be seen by a professional.




Pain Reliefcontrol you pain and move better because often pain is just sensitivity of tissue. The cause of the pain is likely not a big problem other than the tissues in your knee can’t handle the force and load. Taking simple pain relief and anti-inflammatory helps to make you more comfortable and move more freely.

Physiotherapyif your problem is persistent then seeking the help of a physio may be a good idea. They can help to identify any issues with your lower limbs that may be contributing to your problem such as muscular imbalance. They can also provide treatment which regulates your pain and quickens your recovery.

Exercisesee our next section for some basic exercises – but strength work is key to getting this problem better.

Heathot treatments for knees may provide comfort when painful. Hot water bottles, hot packs and heat creams are all great ways to get heat in to the front of the knee.

Knee Support – compression with knee supports and sleeves are great for 2 different reasons. If your knee needs help to bend comfortably then look at a supportive knee joint which can take some of the load off the knee. If the knee is swollen – compression and elevation is recommended.




Combat knee pain when bending with these exercises.

A simple way to look at knee pain when bending is the fact that the knee is not strong enough to perform such a simple task.

Focusing on exercises which strengthen the quads and hamstrings will really help to improve the quality of the knee pain and ability to tolerate load when bending.


Seated Quadriceps Extensionideally this will be performed with a machine in the gym. If you do not have access to a gym, use a resistance band to add weight. This exercise is ideal for knee pain and bending the knee. There is no bodyweight on the knee but the resistance helps to strengthen the knee.

The exercise is simply straightening the knee against resistance and loading the quads.

Ideally repeat in sets of 3-4, performing a minimum of 6 reps in each set.


Hamstring Bridge – Similar to the glute bridge, this one has a slight tweak to it. Reduce the bend in the knee so the legs are slightly straighter, when you are lying on your back with their feet on the floor.

Point your toes to the ceiling and dig your heals in to the floor.

Push through your heels and raise your bum off the floor and take as high as possible. Hold for 5 seconds and slowly lower down. Again aim for 3-4 sets and minimum of 6 reps per set.


TRX Assisted Squats a squat is simply a repetitive bending of the knee. If your knee cannot tolerate bending your own weight, then assist the movement and retrain it.

TRX bands or grabbing on to an object to assist the squat is ideal for retraining your knee bend to not be painful.

You could also do this simply at home using a railing or kitchen bench.

When this improves you can progress to free standing squats – this should then be non painful.

That concludes our guide to knee pain when bending, we hope that this has been helpful. If this has helped you and you think it could help someone you know then please share this article with them.



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